/*
 * Copyright (C) 2001 MontaVista Software Inc.
 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 *
 */

#include	<inc/print.h>

/* macros */
#define		IsDigit(x)	( ((x) >= '0') && ((x) <= '9') )
#define		Ctod(x)		( (x) - '0')

/* forward declaration */
extern int PrintChar(char *, char, int, int);
extern int PrintString(char *, char *, int, int);
extern int PrintNum(char *, unsigned long, int, int, int, int, char, int);

/* private variable */
static const char theFatalMsg[] = "fatal error in lp_Print!";

/* -*-
 * A low level printf() function.
 */
void
lp_Print(void (*output)(void *, char *, int),
		 void *arg,
		 char *fmt,
		 va_list ap)
{

#define 	OUTPUT(arg, s, l)  \
{ if (((l) < 0) || ((l) > LP_MAX_BUF)) { \
			(*output)(arg, (char*)theFatalMsg, sizeof(theFatalMsg)-1); for(;;); \
		} else { \
			(*output)(arg, s, l); \
		} \
	}

	char buf[LP_MAX_BUF];

	char c;
	char *s;
	long int num;

	int longFlag;
	int negFlag;
	int width;
	int prec;
	int ladjust;
	char padc;

	int length;

	for (;;) {
		{
			/* scan for the next '%' */
			char *fmtStart = fmt;

			while ( (*fmt != '\0') && (*fmt != '%')) {
				fmt ++;
			}

			/* flush the string found so far */
			OUTPUT(arg, fmtStart, fmt - fmtStart);

			/* are we hitting the end? */
			if (*fmt == '\0') {
				break;
			}
		}

		/* we found a '%' */
		fmt ++;

		/* check for long */
		if (*fmt == 'l') {
			longFlag = 1;
			fmt ++;
		} else {
			longFlag = 0;
		}

		/* check for other prefixes */
		width = 0;
		prec = -1;
		ladjust = 0;
		padc = ' ';

		if (*fmt == '-') {
			ladjust = 1;
			fmt ++;
		}

		if (*fmt == '0') {
			padc = '0';
			fmt++;
		}

		if (IsDigit(*fmt)) {
			while (IsDigit(*fmt)) {
				width = 10 * width + Ctod(*fmt++);
			}
		}

		if (*fmt == '.') {
			fmt ++;

			if (IsDigit(*fmt)) {
				prec = 0;

				while (IsDigit(*fmt)) {
					prec = prec * 10 + Ctod(*fmt++);
				}
			}
		}


		/* check format flag */
		negFlag = 0;

		switch (*fmt) {
			case 'b':
				if (longFlag) {
					num = va_arg(ap, long int);
				} else {
					num = va_arg(ap, int);
				}

				length = PrintNum(buf, num, 2, 0, width, ladjust, padc, 0);
				OUTPUT(arg, buf, length);
				break;

			case 'd':
			case 'D':
				if (longFlag) {
					num = va_arg(ap, long int);
				} else {
					num = va_arg(ap, int);
				}

				if (num < 0) {
					num = - num;
					negFlag = 1;
				}

				length = PrintNum(buf, num, 10, negFlag, width, ladjust, padc, 0);
				OUTPUT(arg, buf, length);
				break;

			case 'o':
			case 'O':
				if (longFlag) {
					num = va_arg(ap, long int);
				} else {
					num = va_arg(ap, int);
				}

				length = PrintNum(buf, num, 8, 0, width, ladjust, padc, 0);
				OUTPUT(arg, buf, length);
				break;

			case 'u':
			case 'U':
				if (longFlag) {
					num = va_arg(ap, long int);
				} else {
					num = va_arg(ap, int);
				}

				length = PrintNum(buf, num, 10, 0, width, ladjust, padc, 0);
				OUTPUT(arg, buf, length);
				break;

			case 'x':
				if (longFlag) {
					num = va_arg(ap, long int);
				} else {
					num = va_arg(ap, int);
				}

				length = PrintNum(buf, num, 16, 0, width, ladjust, padc, 0);
				OUTPUT(arg, buf, length);
				break;

			case 'X':
				if (longFlag) {
					num = va_arg(ap, long int);
				} else {
					num = va_arg(ap, int);
				}

				length = PrintNum(buf, num, 16, 0, width, ladjust, padc, 1);
				OUTPUT(arg, buf, length);
				break;

			case 'c':
				c = (char)va_arg(ap, int);
				length = PrintChar(buf, c, width, ladjust);
				OUTPUT(arg, buf, length);
				break;

			case 's':
				s = (char *)va_arg(ap, char *);
				length = PrintString(buf, s, width, ladjust);
				OUTPUT(arg, buf, length);
				break;

			case '\0':
				fmt --;
				break;

			default:
				/* output this char as it is */
				OUTPUT(arg, fmt, 1);
		}	/* switch (*fmt) */

		fmt ++;
	}		/* for(;;) */

	/* special termination call */
	OUTPUT(arg, "\0", 1);
}


/* --------------- local help functions --------------------- */
int
PrintChar(char *buf, char c, int length, int ladjust)
{
	int i;

	if (length < 1) {
		length = 1;
	}

	if (ladjust) {
		*buf = c;

		for (i = 1; i < length; i++) {
			buf[i] = ' ';
		}
	} else {
		for (i = 0; i < length - 1; i++) {
			buf[i] = ' ';
		}

		buf[length - 1] = c;
	}

	return length;
}

int
PrintString(char *buf, char *s, int length, int ladjust)
{
	int i;
	int len = 0;
	char *s1 = s;

	while (*s1++) {
		len++;
	}

	if (length < len) {
		length = len;
	}

	if (ladjust) {
		for (i = 0; i < len; i++) {
			buf[i] = s[i];
		}

		for (i = len; i < length; i++) {
			buf[i] = ' ';
		}
	} else {
		for (i = 0; i < length - len; i++) {
			buf[i] = ' ';
		}

		for (i = length - len; i < length; i++) {
			buf[i] = s[i - length + len];
		}
	}

	return length;
}

int
PrintNum(char *buf, unsigned long u, int base, int negFlag,
		 int length, int ladjust, char padc, int upcase)
{
	/* algorithm :
	 *  1. prints the number from left to right in reverse form.
	 *  2. fill the remaining spaces with padc if length is longer than
	 *     the actual length
	 *     TRICKY : if left adjusted, no "0" padding.
	 *		    if negtive, insert  "0" padding between "0" and number.
	 *  3. if (!ladjust) we reverse the whole string including paddings
	 *  4. otherwise we only reverse the actual string representing the num.
	 */

	int actualLength = 0;
	char *p = buf;
	int i;

	do {
		int tmp = u % base;

		if (tmp <= 9) {
			*p++ = '0' + tmp;
		} else if (upcase) {
			*p++ = 'A' + tmp - 10;
		} else {
			*p++ = 'a' + tmp - 10;
		}

		u /= base;
	} while (u != 0);

	if (negFlag) {
		*p++ = '-';
	}

	/* figure out actual length and adjust the maximum length */
	actualLength = p - buf;

	if (length < actualLength) {
		length = actualLength;
	}

	/* add padding */
	if (ladjust) {
		padc = ' ';
	}

	if (negFlag && !ladjust && (padc == '0')) {
		for (i = actualLength - 1; i < length - 1; i++) {
			buf[i] = padc;
		}

		buf[length - 1] = '-';
	} else {
		for (i = actualLength; i < length; i++) {
			buf[i] = padc;
		}
	}


	/* prepare to reverse the string */
	{
		int begin = 0;
		int end;

		if (ladjust) {
			end = actualLength - 1;
		} else {
			end = length - 1;
		}

		while (end > begin) {
			char tmp = buf[begin];
			buf[begin] = buf[end];
			buf[end] = tmp;
			begin ++;
			end --;
		}
	}

	/* adjust the string pointer */
	return length;
}
